Employee Benefit Plans (Additional Information) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended			3 Months Ended	12 Months Ended	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014	Dec. 31, 2011	Jun. 30, 2014	Jan. 28, 2013
Pension and Other Postretirement Benefits Disclosure [Line Items]
Curtailments and special termination benefits	$ 33
Reduction in projected benefit obligation as a result of separation transaction								550
Reduction in accumulated benefit obligation as a result of separation transaction								165
ABO for all defined benefit pension plans		5,624	5,064
Aggregate PBO for the pension plans with PBO in excess of plan assets		4,864	2,377
Aggregate fair value of plan assets for the pension plans with PBO in excess of plan assets		3,879	1,619
Aggregate ABO for the pension plans with ABO in excess of plan assets		4,453	2,242
Fair value of plan assets for the pension plans with ABO in excess of plan assets		3,584	1,617
Expected return on assets		6.50%	6.50%	7.00%
Weighted-average healthcare cost trend rate assumed for next fiscal year		6.30%
Assumed ultimate health care cost trend rate		4.50%
Assumed year that ultimate health care cost trend rate will be reached		2024
Estimated future benefit payments in 2016		68
Estimated future benefit payments in 2017		69
Estimated future benefit payments in 2018		69
Estimated future benefit payments in 2019		70
Benefits paid		61	22
Accrued pensions		995	728
Defined Contribution Plan Contribution Rates As Percentage Of Employees Earnings		6.00%	6.00%	6.00%
Expense (income) of the deferred compensation plan		10	18	10
Deferred Compensation Arrangement With Individual Increase Decrease In Fair Value Of Investments		8	17	8
Realized gains on the investment portfolio of the deferred compensation plan		2.9	3.4	0.9
Obligations under the deferred compensation plan		119	114
Investments in marketable securities by the deferred compensation plan		79	75
Pension Benefit from Plan Reorganization - Commodity Chem Divestiture			18
Defined Contribution Plan Contribution Rate		100.00%	100.00%	75.00%
Deductible dividends on PPG shares held by the ESOP		14	15	18
Pensions
Pension and Other Postretirement Benefits Disclosure [Line Items]
Recognized expense for defined contribution pension plans		55	49	41
Accrued pensions		14	17
Fiscal Years 2013
Pension and Other Postretirement Benefits Disclosure [Line Items]
Weighted-average healthcare cost trend rate assumed for next fiscal year		6.40%
Assumed ultimate health care cost trend rate		4.50%
Assumed year that ultimate health care cost trend rate will be reached		2024
Pittsburgh Glass Works LLC
Pension and Other Postretirement Benefits Disclosure [Line Items]
Costs related to the pension and other postemployment benefit liabilities of the divested business		19	30	35
Liabilities for pension and post-employment benefits earned for service up to the time of sale		945	914
Owen Sound Facility [Member]
Pension and Other Postretirement Benefits Disclosure [Line Items]
Pension Settlement Charge, Canadian wind-up		2	16
Plant closures in Canada, partial wind-ups of the pension plans, settlement charge, low estimate		55
Plant closures in Canada, partial wind-ups of the pension plans, settlement charge, high estimate		70
Plant closures in Canada, pension plan deficit, low estimate		10
Plant closures in Canada, pension plan deficit, high estimate		20
Pensions
Pension and Other Postretirement Benefits Disclosure [Line Items]
Curtailments and special termination benefits		6	18
Fair values of pension plan assets		4,839	4,701	4,750
Estimated amounts of accumulated net actuarial loss that will be amortized from AOCI into net periodic benefit cost in 2012		116
Estimated amounts of accumulated prior service cost that will be amortized from AOCI into net periodic benefit cost in 2012		(2)
Contributions to defined benefit pension plans		41	174
Estimated future benefit payments in 2015		297
Estimated future benefit payments in 2016		286
Estimated future benefit payments in 2017		270
Estimated future benefit payments in 2018		273
Estimated future benefit payments in 2019		276
Estimated aggregate future benefits payments for the five years thereafter		1,425
Benefits paid		390	304
Accrued pensions		995	744
Defined Benefit Plan, Settlements, Plan Assets		4	51
Pensions | Pensions
Pension and Other Postretirement Benefits Disclosure [Line Items]
Curtailments and special termination benefits		8	18
Estimated amounts of accumulated net actuarial loss that will be amortized from AOCI into net periodic benefit cost in 2012		(77)	(102)	(133)
Other Postretirement Benefits
Pension and Other Postretirement Benefits Disclosure [Line Items]
Curtailments and special termination benefits		0	0
Estimated amounts of accumulated net actuarial loss that will be amortized from AOCI into net periodic benefit cost in 2012		32
Estimated amounts of accumulated prior service cost that will be amortized from AOCI into net periodic benefit cost in 2012		(9)
Estimated future benefit payments in 2015		67
Estimated aggregate future benefits payments for the five years thereafter		345
Benefits paid		44	60
Accrued pensions		0	0
United States Pension Plans of US Entity, Defined Benefit
Pension and Other Postretirement Benefits Disclosure [Line Items]
Expected return on assets		7.25%
Contributions to defined benefit pension plans			50	0	2	50
Foreign Pension Plan
Pension and Other Postretirement Benefits Disclosure [Line Items]
Expected return on assets		6.10%
Contributions to defined benefit pension plans		39	124	80
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year, Low end of Range		10
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year, High end of Range		20
United States, Canada, Netherlands and United Kingdom
Pension and Other Postretirement Benefits Disclosure [Line Items]
Percentage of defined benefit pension plan assets market value		96.00%
Commodity Chemicals Segment
Pension and Other Postretirement Benefits Disclosure [Line Items]
Fair values of pension plan assets								421
Defined Benefit Plan, Fair Value of U.S. Pension Plan Assets Transferred to Axiall		86
Defined Benefit Plan, Fair Value of Canadian Pension Plan Assets Transferred to Axiall		11
U.S. Pension Settlement Charges
Pension and Other Postretirement Benefits Disclosure [Line Items]
Defined Benefit Plan, Settlements, Plan Assets							$ 41